Lockable shutter for withdrawable racks of low-voltage power circuit breakers

Abstract

Withdrawable racks for power circuit breakers should be reliably switched. To this end, the movement of the plates of a shutter in the withdrawable rack can be blocked so that the shutter is not permitted to open unintentionally. In a special embodiment, the opening mechanism for the plates can have two V-shaped linkages that are connected to a telescopic rod. The telescopic rod can be locked by a locking element so that the shutter plates, which can be moved by sliders, can no longer be displaced.

1. A closure apparatus for withdrawable insert frames for a withdrawable circuit breaker, comprising:
 a plate arrangement, including at least two plates arranged in parallel and movable with respect to one another, each including at least one opening, the at least one opening in a first plate of the at least two plates being covered, in a closed state, by a second of the at least two plates, and the at least one opening in each of the two plates being located one above the other in an open state; and 
 a movement device for movement of the at least two plates relative to one another, the movement device being blockable such that the plates of the plate arrangement cannot be moved to the open state, and the movement device including pivoting elements, each pivotable about an axis parallel to the plates, to engage in one another in a blocking state, and thus block the movement device. 
 
     
     
       2. The closure apparatus as claimed in  claim 1 , wherein the movement device includes a V-shaped linkage, whose two limbs are mounted in a joint and rotatable, a first limb being fixed by its free end on the first or second plate and a second limb being fixed by its free end on a section of the closure apparatus which cannot move in a direction parallel to the plates. 
     
     
       3. The closure apparatus as claimed in  claim 2 , wherein a variable-length rod device is fixed by one of its ends to the joint of the V-shaped linkage, and is fixed by its other end directly or indirectly to a section of the closure apparatus which cannot move in a direction parallel to the plates. 
     
     
       4. The closure apparatus as claimed in  claim 3 , wherein the length variation of the rod device is blockable. 
     
     
       5. The closure apparatus as claimed in  claim 2 , wherein the movement device, includes a greater extent at right angles to the plates in its blocked state than in its unblocked state. 
     
     
       6. The closure apparatus as claimed in  claim 2 , further comprising a displacement device for movement of the closure apparatus at right angles to the plates. 
     
     
       7. The closure apparatus as claimed in  claim 2 , further including a tension spring between the two limbs of the V-shaped linkage. 
     
     
       8. The closure apparatus as claimed in  claim 1 , wherein the plate arrangement includes three parallel plates, one of the plates being fixed in position with respect to the closure apparatus in a direction parallel to the plates and used as an mask, and the two other plates being movable. 
     
     
       9. The closure apparatus as claimed in  claim 8 , wherein the displacement movement of each of the movable plates corresponds essentially to half the extent of the at least one opening in the movement direction. 
     
     
       10. The closure apparatus as claimed in  claim 9 , wherein each of the movable plates is coupled by in each case one V-shaped linkage to the fixed-position plate, and the joints of the two V-shaped linkages are coupled to the rod device. 
     
     
       11. The closure apparatus as claimed in  claim 8 , wherein each of the movable plates is coupled by in each case one V-shaped linkage to the fixed-position plate, and the joints of the two V-shaped linkages are coupled to the rod device. 
     
     
       12. The closure apparatus as claimed in  claim 1 , wherein the movement device includes a greater extent at right angles to the plates in its blocked state than in its unblocked state. 
     
     
       13. The closure apparatus as claimed in  claim 1 , further comprising a displacement device for movement of the closure apparatus at right angles to the plates. 
     
     
       14. The closure apparatus as claimed in  claim 1 , wherein the pivoting elements include at least one hole that align over one another when the pivoting elements overlap one another. 
     
     
       15. The closure apparatus as claimed in  claim 1 , wherein each of the at least two plates are laterally movable. 
     
     
       16. A method for protecting a withdrawable insert frame against unauthorized insertion of a withdrawable circuit breaker, the method comprising:
 provisioning a closure apparatus including a movement device and a plate arrangement of at least two plates arranged in parallel and movable with respect to one another in the withdrawable insert frame each including at least one opening, the at least one opening in a first plate of the at least two plates being covered, in a closed state, by a second of the at least two plates, and the at least one opening in each of the two plates being located one above the other in an open state; and 
 detachably blocking a movement device of the closure apparatus such that the plates of the plate arrangement cannot move to an open state, the blocking of the movement device being achieved by engaging two pivoting elements with one another, the pivoting elements in each case being pivoted about an axis parallel to the plates. 
 
     
     
       17. The method as claimed in  claim 16 , wherein the movement of the withdrawable circuit breaker is limited to the closure apparatus by use of the pivoting elements. 
     
     
       18. A method for insertion of a withdrawable circuit breaker into a withdrawable frame, comprising:
 provisioning a closure apparatus including a movement device and a plate arrangement of at least two plates arranged in parallel and movable with respect to one another in the withdrawable insert frame each including at least one opening, the at least one opening in a first plate of the at least two plates being covered, in a closed state, by a second of the at least two plates, and the at least one opening in each of the two plates being located one above the other in an open state; and 
 releasing blocking of the movement device of the closure apparatus such that the plates of the plate arrangement can move to the open state, the blocking being released by releasing the engagement of two pivoting elements which are fitted to the movement device, by pivoting the pivoting elements about an axis parallel to the plates. 
 
     
     
       19. The method as claimed in  claim 18 , wherein the plates are moved to the open state and then moved further at right angles to this movement, corresponding to the movement of the withdrawable circuit breaker, during insertion of the withdrawable circuit breaker into the withdrawable insert frame.